Apparatus for winding heat exchangers



3 Sheets-Sheet 1 Filed July 19, 1946 gill/III,"

Final/Ill Jan. 10, 1950 s. c. COLLINS 2,494,286

APPARATUS FOR WINDING HEAT EXCHANGERS Filed July 19, 1946 s Sheets-Sheet2 Jan. 10, 1950 s. c. COLLINS 2,494,286

APPARATUS FOR WINDING HEAT EXCHANGERS Filed July 19, 1946 '3Sheets-Sheet 3 UNITED STATES PETENT OFFICE APPARATUS -FOR ENDING HEATEXCHANGERS Samuel 0. Collins, Watertown, Mass. Application July 19,1946, Serial No. 684,744

(Cl. l13-1) 2 Claims.

This invention relates to apparatus for winding a heat exchanger of thetype having a central core or tube with helically wound fins integrallyabout the core tube so that a predetermined pitch and fin spacing may besecured, and'when thus wound, the parts may be integrally joined orunited without disturbing the wound fin material; and to provide asimple and reliable apparatus which may be so adjusted as to vary theamount of fin material applied to a predetermined length of core tube soas to secure any desired pitch and fin spacing.

Further objects relate to various features of construction and will beapparent from a consideration of the following description and theaccompanying drawings, wherein:

Fig. 1 is a side elevation of a winding machine constructed inaccordance with the present invention;

Fig. 2 is a fragmentary end elevation showing the gear train associatedwith the lead or feed screw and supporting means for the core tube;

Fig. 3 is an enlarged front elevation of the traveling feed mechanism:

Fig. 4 is an enlarged section through the finfeeding tube;

Fig. 5 is an end elevation of the tin-feeding tube;

Fig. 6 is a section approximately on th line 6-6 of Fig. 7 is a top planview of the transmission mechanism;

Fig. 8 is an enlarged vertical section through the lead screw andassociated sleeve;

Fig. 9 is an enlarged fragmentary elevation showing a core tube with finmaterial and solder wound thereon; and

Fig. 10 is a view, similar to Fig. 9, but showing the parts after havingbeen subjected to a heat treatment efi'ective to unite the fin materialto the wound tube.

The embodiment herein shown for the purpose of illustration comprises anelongate bed I having adjacent to each end upstanding brackets 2 and 3.Along one side of the bed is a pair of spaced angle irons providing atrack 4 on which a carriage 5 runs, as illustrated in Figs. 1 and 6. Thebrackets 2 and 3 are formed with aligned openings through which projectthe ends of a lead screw 8 formed with a keyway l0 (Fig. 3)

2 which extends from one end to the other, and one end of the lead screwcarries a collar II and its opposite end carries a gear l2 (Fig. 1).

The bracket 2 is provided with an opening disposed below and in ofi'setrelation to the gear I2. and rotatably mounted in this opening is acylindrical member or chuck l5, the inner end of which projects into abore of a core tube T so as to provide a means for supporting androtating the tube. The outer end of the chuck |5 projects beyond thebracket 2' and carries a gear IS. A stub shaft 20. interposed between,the gears l2 and It, carries a gear 2| which meshes with the gear l2 anda second gear 22 which meshes with the gear Hi, the construction beingsuch that a given rate of rotation of the lead screw 8 is transmittedthrough gears l2, 2|, 22 and I8 to effect a predetermined rotation ofthe core tube T.

The carriage 5 (Figs. 3 and 6) comprises a flat body or deck 25 havingdepending forks 26 which carry rollers 28 that run on the track 4.Mounted at opposite ends of the deck 25 are brackets 30 and 3| and posts32 and 33 (Figs. 1 and 3). Along the inner side edge of the deck 25 is asmall housing 35, the opposite ends of which are provided with openingsaligned with the chuck l5 and through which the core tube T extends, asshown in Figs. 1, 3 and 6. The housing 35 provides a support for thecore tube adjacent to the section which is being wound and thuscooperates with the chuck IS in rotatably supporting tube T.

The bracket 30 carries a pair of inwardly projecting cars 38 (Figs. 3and '7) which rotatably support a feeding tube 40 integrally joined to agear 4|. The bore of the feeding tube 40 is of a size freely to receivethe helical fin material F and its delivery end carries a small plate orsector 42 which projects into the bore to provide, in efiect, a feedingthread engageable with one or more convolutions of the helical finmaterial F, as illustrated in Fig. 4, so that upon rotation of the tube40 the fin material is fed outwardly. The upper end of the bracket 3|)is provided with an extension 44 which carries an interiorly threadedsleeve 45 which fits about the lead screw 8 so that rotation of the leadscrew causes the carriage 5 to move along the track 4.

The upper end of the bracket 3| carries a pair of collars 48 whichloosely fit about the leadscrew 8 and one end of an inverted U-shapedfinger 50 is welded or otherwise secured to the top edge of the bracket3| so that its depending free end is juxtaposed to the outer face of adriving gear 52 circumposed about the lead screw 8.

3 The gear 52 is integral with a hub 5| (Fig. 3) which is splined to thelead screw 8 by a key I! (Fig. 6) loosely fitting the keyway HI so as topermit a free sliding movement of the gear and hub along the lead screw.When the gear 52 is rotated, as hereinafter described, the lead screw isrotated and not only operates through sleeve 45 to move the carriagealong track 4, but also operates as a drive shaft acting through thegear train l2, 2|, 22 and I8 to rotate the core tube T.

The upper end of the posts 32 and 33 are bent forwardly and support arod 60 (Figs. 1 and 3) which is parallel to and in approximate verticalalignment with the core tube T. The rod 60 rotatably supports a supplyspool SI of solder S or the like fusible metallic strand material whichis effective when fiuxed to solder, weld or otherwise secure the finmaterial FM to the core tube T. Where the core tube and fin material areof copper or a copper alloy, the solder S may be of the conventionaltype. The upper end of the housing 35 carries a guiding member 66 (Fig.3) which overhangs the core tube T in advance of the feeding tube Ml soas to permit the strand of solder to be wound about the tube T ahead ofthe fin material, as illustrated in Figs. 1 and 3.

The fin-feeding gear ll and the driving gear 52 are preferably drivenfrom the same source and accordingly an electric motor 10 is mounted onthe deck 25 rearwardly of the lead screw 8. The motor In is coupled witha transmission mechanism 12 (Figs. 6 and 1) which is connected throughsuitable gear trains to the gears ll and 52. As shown in Figs. 6 and 7,the transmission mechanism 12 comprises a worm II and gear 15 bothmounted on the shaft of the motor 10, the gear I5 meshing directly withthe feed gear 4|. The worm l4 meshes with a small worm gear 18 fast to ashaft 80, the opposite ends of which are mounted in brackets 8| and-82projecting upwardly from the deck 25. The shaft 80 carries a gear 84(Fig. 6) which meshes directly with the gear 52. With this constructionand arrangement of parts the motor 10 operates through gear 15 to rotatethe fin-feeding tube 40 and through worm It, gears 18, 84 and 52 torotate the lead screw 8. By selecting suitable gears the rates of feederspeed and carriage travel may be adjusted to the desired value, andsince the core tube T is driven b lead screw 8, selection of suitablegears l2, l8, 2i and 22, the desired pitch of the helix defined by thefin material F may be secured. Thus, the rate of feed of the finmaterial F, the rate of rotation of the core tube T and the rate oftravel of the carriage 5 may be varied so as to obtain any desired pitchand spacing of the fin material on the core tube.

For the purpose of illustration the particular apparatus herein shown isset up to wind fin material on a copper tubing having an O. D. of 0.802"x 0.025" wall and a length up to about 10 feet. The fin material Fconsists of rectangular copper wire, 0.01" x 0.04" cross section, woundon a 0.058" mandrel to provide a helix having an O. D. of about 0.133".Assuming that the proper selection of gears has been made to produce awinding having the desired fin spacing and pitch, the carriage 5 isfirst moved to a position adjacent to the bracket 2 (left-hand end asviewed in Fig. 1) and a length of tube T to be wound is inserted throughthe openings in the housing 35 and its end fastened about chuck IS. Aspool SI of 50-50 solder S (0.032") is mounted on the rod ill and theend of the solder is threaded through guide 54 and soldered to orotherwise held against the tube T. The motor It is then started so as toapply about 4 convolutions of solder about the tube T and is thenstopped. The fin material 1'' is then threaded through the feeding tube10, as shown in Fig. 4, and its end is spot soldered to or otherwiseheld against the tube T in contiguous relation to the solder S. Theapparatlm is now ready for operation and the motor may be turned on,thereby simultaneously effecting rotation of the tube T, feeding andapplication of the fin material F and solder S and travel of thecarriage 5 toward the opposite end of the bed.

During the winding operation the solder S is tightly wound about thetube T and defines, in effect, a helical groove which receives the finmaterial F, the individual fins of which are contiguous to the strandsof solder which prevent displacement of the fin material axially of thetube. as illustrated in Fig. 9. After substantially the entire length oftube T has been wound, the solder and fin material may be severed andtheir free ends spot soldered or otherwise secured to the tube,preparatory to the next step of subjecting the wound tube to a heattreatment effective integrally to unit the fin mtaerial and tube.

The tube thus wound with fin material and solder or other fusible metalmay be sprayed with or dipped into a suitable flux, such as a zincchloride-hydrochloric acid mixture or the like, after which it issubjected to a temperature sufficient to melt the solder or fusiblemetal and to this end the wound tube may be placed in a. gas furnace oran induction furnace, or it may be subjected to the action of a blowtorch or any other suitable procedure. Due to capillary action, thefiuxed solder migrates to the area about the points of tangcncy of theindividual fins and the surface of the tube T so that, upon cooling, thesolder forms a fillet 98, as illustrated in Fig. 10, which integrallyunites the fin material to the tube T and insures a relatively highdegree of thermal-conductivity between the fin material and tubing.

If desired, the tube T may be wound with only the fin material, in whichcase the wound tube is first treated with a suitable flux, after whichit may be dipped in a bath of molten solder or other fusible metal,withdrawn, and the tube then shaken, centrifuged or otherwise treated toremove excess solder. Due to capillary action, the molten solder is heldabout the points of tangency of the individual fins and surface of thetube T and. upon cooling, provides a fillet 90, as illustrated in Fig.10.

After having built up one heat exchanger tube, as illustrated in Fig.10, it may be inserted through an outer tube T of copper or the likematerial and the assemblage then drawn through a suitable die effectiveto contract the outer tube T about the wound-core tube T. The contractedouter tube may then be wound with fin material, solder, etc., as abovedescribed, to provide a second heat exchanger element or unitconcentrically disposed about the first. This procedure may then berepeated so as to build up a heat exchanger having any desired number ofconcentric units, each consisting of a core tube wound with fin materialand integrally united thereto by a fillet of solder.

While I have shown and described one desirable embodiment of theinvention, it is to be understood that this disclosure is for thepurpose of illustration and that various changes and modifications may bmade without departing from the spirit and scope of the invention as setforth 5 in the appended claims.

I claim:

1. Apparatus for winding fin material about a core tube, comprising anelongate bed having a track extending from one end to the other, abracket adjacent to one end of said bed, means carried by said bracketfor rotatably supporting the core tube, a rotatable lead screw extendingparallel to said track, a carriage mounted on said track and havingmeans engaging said lead screw so that rotation of the latter causessaid carriage to move along said track, a feed tube rotatably mounted onsaid carriage and through which said fin material passes, means carriedby said feed tube and engageable with the fin material therein forfeeding the fin material outwardly when said feed tube is rotated, guidemeans mounted on said carriage in advance of said feed tube for applyinga fusible metal strand to the core tube, and means for simultaneouslyrotating said feed tube, said core tube and said lead screw so as toeffect a predetermined rate of feed of said fin material relative to therate of rotation of said core tube and axial travel of said carriage.

2. Apparatus for winding helical fin material about a core tube,comprising an elongate bed having a track extending from one end to theother, upstanding brackets at each end of said bed, a chuck carried byone of said brackets for rotatably supporting the core tube, a leadscrewrotatably supported by said brackets in spaced parallel relation to saidtrack, connections between said lead screw and chuck so that rotation ofsaid lead screw effects a rotation of said chuck, a carriage mounted onsaid track, a motor mounted on said carriage, a rotatable feeding tube35 mounted on said carriage, means carried by said 6 feeding tube andengageable with the convolutions of said fin material for feeding saidfin material outwardly at a predetermined rate when said feeding tube isrotated, guide means on said carriage in advance of said rotatablefeeding tube for applying a fusible metal strand to the core tube, athreaded member engaging said lead screw and connected with saidcarriage so as to cause said carriage to move along said track inresponse to rotation of said lead screw, and connections between saidmotor, said rotatable feeding tube and lead screw operativesimultaneously to rotate said feeding tube and said lead screw atpredetermined relative rates and thereby etiect a predetermined rate oftravel of said carriage along said track.

SAMUEL C. COLLINS.

REFERENCES CITED The following references are of record in the file ofthis patemt:

UNITED STATES PATENTS

